title: Added value of PCR-testing for confirmation of invasive meningococcal disease in England.
abstract: OBJECTIVE
  In England, national guidance recommends that all patients with suspected invasive meningococcal disease (IMD) should be investigated by blood culture and polymerase chain reaction (PCR) testing. The Meningococcal Reference Unit (MRU) provides a national service for meningococcal species confirmation and PCR-testing of clinical samples. We performed a population-level assessment of the added value of PCR-testing for IMD to augment traditional culture confirmation.
  
  
  METHODS
  We analysed all PCR-samples and invasive meningococcal isolates received by MRU in 2009 and 2010. We assumed that all patients with PCR-samples submitted to MRU also had blood cultures performed and that positive blood cultures were referred to MRU. We confirmed this assertion by case ascertainment.
  
  
  RESULTS
  In total, 25,379 specimens from 22,039 patients were submitted for PCR-testing and 1492 (6.8%) tested PCR-positive. MRU received 825 invasive meningococcal isolates; 393 confirmed by PCR and culture, 405 without a PCR-specimen submitted and 27 with a PCR-negative result. Thus, of 1924 reported IMD cases, 1099 (57.1%) were confirmed by PCR only, 432 (22.5%) by culture only and 393 (20.4%) by both tests.
  
  
  CONCLUSIONS
  More than half of all confirmed IMD cases were confirmed by PCR only, indicating this service ensures high case ascertainment for national surveillance.
authors.affiliation: European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden; Immunisation, Hepatitis & Blood Safety Department, Public Health England, London, United Kingdom.
authors.forename: Ellen
authors.initials: E
authors.lastname: Heinsbroek
authors.forename: Shamez
authors.initials: S
authors.lastname: Ladhani
authors.forename: Steve
authors.initials: S
authors.lastname: Gray
authors.forename: Malcolm
authors.initials: M
authors.lastname: Guiver
authors.forename: Ed
authors.initials: E
authors.lastname: Kaczmarski
authors.forename: Ray
authors.initials: R
authors.lastname: Borrow
authors.forename: Mary
authors.initials: M
authors.lastname: Ramsay
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008589:Meningococcal Infections / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology*; D008875:Middle Aged; D058889:Molecular Typing / Q000379:methods; D009345:Neisseria meningitidis / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Bacterial infections; Diagnosis; Invasive meningococcal disease; Meningococcal infections; Neisseria meningitidis; Polymerase chain reaction; Surveillance